odoo, how can I add internal reference to quotation report?

Question

I need to add the internal reference default_code to the quotation report sale_report_template.xml.

I tried using

   <t t-foreach="layout_category['lines']" t-as="l">
                                <tr>
                                    <td><span t-field="l.default_code"/></td>

but can't seem to get it to work.

Answer 1

 <t t-foreach="layout_category['lines']" t-as="l">
                                <tr>
                                    <td><span t-field="l.product_id.default_code"/></td>